TILs expanded with KT64/BBL aAPCs are comprised of favorable T cell subsets. (a) TILs expanded with aAPC are preferentially comprised of CD8+ T cells. TILs or TALs expanded for 9-11 days under conditions of REM, CD3/28 beads, continued IL-2 growth (600 IU/mL) or aAPC were evaluated for CD4 and CD8 T cells composition. All expanded TIL or TAL cultures were uniformly comprised of CD3+ T cells. Mean ± SEM of six independent expansions is shown. Asterisk indicates a statistically significant increase in CD4:CD8 ratio relative to all other conditions (p < 0.04). (b) Higher CD4: CD8 T cell ratios are observed with increased aAPC: TIL ratios. The result of a representative TIL expansion experiment is shown. (c) FOXP3+ CD4 T cell frequencies are low following aAPC-based expansion. TILs or TALs stimulated and cultured under various conditions for 9-11 days were stained for CD3, CD4 and FOXP3. At day 9-11 post stimulation, TILs had returned to resting TIL cell size. Mean ± SEM of six independent expansions is shown. Asterisk indicates a statistically significant increase in FOXP3+ CD4 T cell frequency relative to all other conditions (p < 0.05).